This invention relates generally to doors, and more particularly to a security door that is especially designed to withstand attempts to force it open.
Ordinary doors can be kicked, pried or forced open, the portion of the jamb near a dead bolt being broken by the force. One approach to this problem is to build up or otherwise strengthen the jamb adjacent the bolt plate. Another approach, disclosed in U.S. Pat. Nos. 915,397 and 4,294,040, is to spread the force over the entire jamb or over the entire door frame.
U.S. Pat. No. 915,397 discloses a vault door movable by sliding and swinging. The door can be manually swung open and closed. When the door is closed, the outer edge of the vault door is slidable into a vertical channel in the door jamb to protect against the door being blown open. The door is locked by rotation of a hand wheel, which by turning a screw drives two levers, thereby pushing the door (on pivot balls) into the channel in the door jamb. When the door slides into the channel, projections on the top and bottom of the door engage ribs on the top and bottom of the door frame, a bolt engages the inner edge of the door, and projections on the inner edge of the door enter recesses in the door jamb. However, this door is heavy and unwieldy to open and close which makes it unsuitable for residential and many commercial buildings.
U.S. Pat. No. 4,294,040 discloses a two-part safety door for buildings and rooms which is intended for use in residential houses. The door comprises a door body and a supporting column, slidable from an unsecured position to a secured position wherein the outer vertical edge of the door body is received in a cavity in the jamb. The door can be locked in the secured position by vertical latches. When a handle is pulled, the door body and the supporting column slide on guides. In its unsecured position, the door body can rotate on hinges attached to the supporting column. Since both the door and the supporting column must be manually slid to secure this door, this door is unwieldy for many people and uses. In addition, the door and supporting column must be manually slid to the unsecured position.
Accordingly, there is a need for a security door which is capable of withstanding kicking or prying without breaking open and which may be easily opened by those, including handicapped people or children, who are authorized to do so. Some means should be provided so that such a door may be shifted to its secured position without requiring the user to pull or push the door, and means should be provided for returning the door to its unsecured position when the door is unlocked. In addition to a secured position within the jamb, such a door should be capable of being latched or locked in the closed (but unsecured) position in the same way that a conventional door is locked.